Sharif Digital Repository

Rare earth elements (REEs) are becoming significant due to their huge applications in many industries, large-scale mining and refining activities. Increasing usage of such metals pose negative environmental impacts. In this research ICP-MS has been used to analyze soil samples collected from former ex-mining areas in the depths of 0–20 cm, 21–40 cm, and 41–60 cm of residential, mining, natural, and industrial areas of Perak. Principal component analysis (PCA) revealed that soil samples taken from different mining, industrial, residential, and natural areas are separated into four clusters. It was observed that REEs were abundant in most of the samples from mining areas. Concentration of the... 

An on-line extraction/determination set up was designed for micro solid-phase extraction of clodinafop propargyl from water, soil and wheat samples using electrospun polyamide nanofiber mats. The prepared mats were packed in a stainless steel tube which conveniently acted as a high-performance liquid chromatography injection loop. Influential parameters affecting the extraction efficiency were optimized using a distilled water sample fortified with 25 μg L-1 of clodinafop propargyl. An enrichment factor of 440 was achieved for clodinafop propargyl indicating the ability of the whole procedure. Under the optimum conditions, the linearity for the analyte was in the range of 6-700 μg L-1, while... 

The paper presents a numerical finite difference model of self-boring pressuremeter test (SBPM) using FLAC software. Different cavity expansion theories in sand have been compared to the results of numerical analyses carried out in this study. Limit pressure is believed to be used as a key parameter for the estimation of soil parameters from pressuremeter tests. In practice, SBPM tests are conducted up to 10–15% cavity strains, and the strain level associated with the limit pressure state is not reached. Therefore, determination of limit pressure usually needs extrapolation. In this paper, the authors suggest to use cavity pressure at 10% strain (P10) for the interpretation of in situ... 

The seismic response of soil depends on proper evaluation and use of soil dynamic properties, including shear modulus and damping ratio at various strain levels. Despite extensive studies on the shear modulus and damping ratio of saturated soils, research on the dynamic properties of unsaturated fine-grained soils — especially at high suction — is limited. This study aims to investigate the dynamic properties of loess at a variety of initial states resulting from different specimen preparation techniques (reconstituted, recompacted, and intact) and their evolutions due to suction-induced desiccation. Results of resonant column tests show that at initial states, the specimen preparation... 

Fluopyram, flupyradifurone, and indaziflam are novel systemic pesticides developed by Bayer. Based on available data, these pesticides appears to have a favorable safety profile in the case of pesticide residue problems. Herein, we report an effective analytical method for the determination of novel pesticides were developed using ultra-high performance liquid chromatography with tandem mass spectrometry coupled with a quick, easy, cheap, effective, rugged, and safe procedure. These target compounds were extracted with acetonitrile and cleaned up with PSA, and were separated successfully between 10.2 and 18.3 min using a C18 chromatographic column connected to an electrospray ionization... 

Mathematical simulation of non-isothermal multiphase flow in deformable unsaturated porous media is a complicated issue because of the need to employ multiple partial differential equations, the need to take into account mass and energy transfer between phases and because of the non-linear nature of the governing partial differential equations. In this paper, an analytical solution for analyzing a fully coupled problem is presented for the one-dimensional case where the coefficients of the system of equations are assumed to be constant for the entire domain. A major issue is the non-linearity of the governing equations, which is not considered in the analytical solution. In order to...